In the conventionally known wireless communication technique, an uplink (also called upstream or upstream link) generally means a link transmitting data from a mobile station apparatus to a base station apparatus when communication is performed between the base station apparatus and the mobile station apparatus in cellular communication or the like. In this uplink, the base station apparatus receives signals from various mobile station apparatuses at the same time. Thereby, when received power is the same among the signals, reception process is easily performed and an excellent reception characteristic is obtained. For realizing this condition, there is introduced a system of controlling a transmitted power of a signal transmitted from the mobile station apparatus, which is called transmit power control (TPC).
The communication method used for a mobile phone of 3G (third generation) is CDMA (Code Division Multiple Access), and the plural mobile station apparatuses use respective codes different form one another and access the base station apparatus using the same frequency, and thereby the TPC is generally required to have a high accuracy and a high speed. Meanwhile, in a standard of the mobile phone for the next generation (3.9G), DFT-S-OFDMA (Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiple Access) is to be used as an uplink communication method, in which the TPC is not required to have a high accuracy and a high speed as in the TPC used in CDMA but the TPC is specified for the purpose of appropriately controlling interference to a neighboring base station apparatus (Non-patent document 1).
TPC methods are broadly divided into two and called an open loop and a closed loop, respectively. In an brief explanation assuming the use of the TPC in the uplink, the TPC of the open loop is a control method in which the mobile station apparatus controls the transmitted power by judgment of the mobile station apparatus and the TPC of the closed loop is a control method in which the transmitted power is controlled by an instruction from the base station apparatus.
In the open loop, there is a method in which an attenuation amount is estimated by the use of transmitted power transmitted from the base station apparatus and received power actually received by the mobile station apparatus, and transmitted power of the mobile station apparatus is determined from the estimated attenuation amount and received power required by the base station apparatus. Meanwhile, in the closed loop, there are a method in which the base station apparatus measures the received power and notifies a short or over amount thereof and a method in which the base station apparatus notifies increase or decrease of the transmitted power in the mobile station apparatus by the use of an error rate of a transmitted signal or the like.